The Mahaska County Courthouse was erected on this site in 1845 as a two-story wooden structure that served not only as a courthouse but also for frontier frolics including church services, operas, and a Native American dance in 1849. In 1876, Mahaska State Savings Bank bought the old courthouse corner for $6,000.00 and built a two-story brick building considered a real beauty at the time, then merged into the Oskaloosa National Bank in 1879. For fifty-four years, the Oskaloosa National Bank printed more than $1,000,000.00 in national currency in eight different denominations, but during the Depression it was one of three out of four banks in Oskaloosa that failed. After a fire broke out next door on the evening of April 22, 1896, the bank remodeled the front entry with a sandstone portico, marble pillars, and iron gates on the doors to protect against loafers. Iowa Trust and Savings Bank purchased the building in 1937 and began operations there, and in 1943 extensive midcentury modern renovations removed its copper and brass grillwork for donation to the World War II scrap metal drive. During a 2009 renovation, the pillars that had originally supported the front portico were found in a local yard, recovered, and returned to support the portico once again.